1. Field of the Invention
The present invention relates generally to foam-in-place seals for use in automotive parts and the like. More particularly, the present invention relates to a combination foam-in-place seal and reverse faced adhesive strip manufactured independently of the vehicle component to which it is subsequently applied.
2. Description of the Prior Art
Foam-in-place gaskets and seals are relatively well known in the prior art, particularly in use with vehicle automotive parts such as brake plate modules or other associated components. The gasket/seal provides a degree of environmental insulation to the passenger compartment, such as by sealing the interior compartment from external moisture and other contaminants, as well as by providing a measure of sound protection. Traditionally, parts requiring foam-in-place beads or seals usually achieve a bond through mechanical or chemical bonding to one of the part""s surfaces. The part with the seal is then mechanically or otherwise attached to an opposing surface to complete the seal.
Referring to FIG. 1, an example is illustrated at 2 in the prior art of a silicone based and foam-in-place gasket applied directly to a conventional and typically bulky part such as a vehicle brake plate module 4. The brake plate module 4, as is well known in the art, attaches at a specified location of the vehicle floor board (not shown) and includes apertures 6 and 8 defined to communicate the steering column and brake control pedals with the vehicle""s engine compartment and to further facilitate mounting of the brake cylinder (also not shown). As is also well known, a plurality of bolts or like fasteners 10 engage the module 4 to the vehicle frame.
The foamable-in-place gasket is again specifically illustrated at 12 and is applied as a desired arrangement of elongated beads directly to the abutting or sealing face of the part, typically in mass production applications by an assembly including a computer numeric controller (CNC), a robotic arm and an extruded silicone delivery system. In many instances, it is typical that the vehicle part (such as again including the brake plate module) is manufactured at a first location and the part is then shipped to a second location for application of the gasket sealant. The part is then typically reshipped back to the first location or to a further assembly location for incorporation within the vehicle.
While providing an effective assembly for producing a formable-in-place sealant gasket directly to a vehicle component, it has been found that significant cost and delay are encountered in shipping the part between the producer, sealant applicator and vehicle assembler. It has further been determined to be impracticable, particularly from an economic perspective, to combine the part manufacture and robotic sealant application steps at one location. This is due in large measure to the disparity in the technology required to stamp the part (relatively straightforward), as opposed to that required to apply the gasket sealant in a repetitive and highly accurate fashion (more sophisticated).
Another example of a method of making a foamed-in-place gasket is set forth in U.S. Pat. No. 4,834,824, issued to Tiedeck and which teaches a coated release board mounted upon a work support and upon which is robotically applied a continuous sealant bead in a predetermined pattern corresponding to a pattern of securing engagement of a workpiece, such as a window assembly, to a vehicle body. The gasket and cardboard release board assemblies are stacked in cartons and shipped to a further location where additional method steps are employed, including applying the sealant bead and release board to the workpiece with the sealant bead retained in securing engagement with the work piece. Thereafter, the release board is stripped from the sealant bead and the work piece (window assembly) is secured to the support such as a vehicle body.
U.S. Pat. No. 5,440,849, issued to Agrawal et al., teaches a vehicular panel assembly and method for making which includes a gasket formed of a polymeric material located within a support fixture for bonding to a sheet-like panel. At least one panel surface to receive the gasket is primed with a bonding reagent and is typically preheated before receiving the gasket. The panel and preset gasket are then pressed together and locator pins are used to position the panel with respect to the gasket. Once located, heat and pressure are applied to complete the bond.
U.S. Pat. No. 4,643,863, issued to Martini, teaches a process for depositing, on a non-adhesive support, a thread of fluid material for gasket manufacture from a nozzle displaced above the support along a path coinciding with the gasket layout. A stiff, wire-like reinforcement is placed on the support before deposition and corresponds to the shape of the gasket to be manufactured. The reinforcement further includes an adhesive surface with respect to the fluid material of the gasket to facilitate the creation of a bond therebetween.
Finally, U.S. Pat. No. 4,356,676, issued to Hauptman, teaches a sealant strip for use between abutting building elements, such as structural elements/logs or the like. The sealant strip is constructed as a generally three dimensional shaped object and includes a synthetic foamed resin core and a pressure sensitive adhesive coating on at least one of two opposed sides of the core. Thin, preferably silicone rubber sealing layers are cured on the two remaining surfaces of the core. The strip is adapted for adhesive attachment to and compression between structural members, with the core supporting the edges of the sealing layers in contact with the opposed surfaces of the structural elements between which the strip has been compressed.
The present invention is a combination attachable sealant bead and strip for application to a vehicle part as a gasket, which provides the same quality and degree of sealing and insulation as provided by prior art mechanically/chemically bonded foam-in-place seals, and which is also an improvement over the prior art in that the bead and strip can be separately produced and then shipped to the part manufacturer for low tech and adhesive application to the part. The present invention improves over conventional procedures which require that the manufactured part, due to economic realities, be shipped to an application station for application of the gasket and then reshipped to the eventual vehicle assembler. The ability to separately produce and ship the bead and strip gasket to the part manufacture results in significant savings of time and money.
The gasket is typically in the form of a carrier strip constructed of a flexible material, such as a high-tear strength polyester, polyolefin, polyolefin foam or polystyrene, with a specified width and thickness and which includes a first face and a second face. The first face of the carrier strip is impregnated with an adhesive and tacking surface. A peel-away backing surface is secured over the first face of material.
One or more elongate beads of material are fixedly applied upon the second face of the carrier strip in a desired pattern. The beads of material are in the preferred embodiment a foam-in-place silicone material which, upon curing, affixingly secures to the second (typically shiny) surface of the plasticized carrier strip.
In use, the carrier strip defines a pattern or loop of given shape and the adhesive surface is applied to the sealing surface of the part, after removal of the peel away backing surface, to affix the carrier strip and so that the bead pattern projects from the opposite second face and in a direction away from the part""s sealing surface. The construction of the carrier strip and bead provides adequate sealing against petroleum, water and air at operating temperatures ranging between xe2x88x9230xc2x0 C. and 180xc2x0 C. and in use as a gasket to seal an area defined between an engaging and sealing surface of the part and an opposing surface, such as again typically including a vehicle passenger compartment or some other desirable application.